Wireless power transmitting and charging system

ABSTRACT

A wireless power transmitting and charging system is disclosed. A method for operating a power transmitter of the wireless power transmitting and charging system comprises the steps of: maintaining a ping value table where ping signal conditions are mapped according to the height of a power receiver; recognizing the power receiver by varying a ping signal according to the ping signal conditions recorded in the ping value table; and controlling a charging mode according to a message received from the power receiver.

TECHNICAL FIELD

The present invention relates to a wireless power transmitting andcharging system for transmitting and receiving power wirelessly.

BACKGROUND ART

A wireless power transmitting system includes a wireless powertransmitter for transmitting electrical energy wirelessly and a wirelesspower receiving device for receiving electrical energy from the wirelesspower transmitter.

Using the wireless power transmitting system, for example, just byplacing a mobile phone on a charge pad, not connecting the mobile phonewith a separate charge connector, it is available to charge a battery ofthe mobile phone.

The techniques for transferring electrical energy wirelessly may bedivided into a magnetic induction technique, a magnetic resonancetechnique and an electromagnetic wave technique according to theprinciple of transmitting electrical energy.

The magnetic induction technique is a technique of transferringelectrical energy utilizing the phenomenon that electricity is inducedbetween a transmitter coil and a receiver coil.

The magnetic resonance technique is a technique of generating magneticfield that oscillates with a resonance frequency in a transmitter coiland transferring energy intensively to a receiver coil designed with thesame resonance frequency.

The electromagnetic wave technique is a technique of receivingelectromagnetic wave using several rectennas in a receiver andtransforming it to electrical energy.

Meanwhile, the wireless power transmission technique may also be dividedinto a flexibly coupled wireless power transfer technology (hereinafter,referred to as a ‘flexibly coupled technology’) and a tightly coupledwireless power transfer technology (hereinafter, referred to as a‘tightly coupled technology’) according to a shape or a strength of themagnetic resonant coupling of a transmitter coil and a receiver coil.

In the case of the ‘flexibly coupled technology’, since magneticresonance coupling may be formed between a single transmitter resonatorand a plurality of receiver resonators, the Concurrent Multiple Chargingmay be available.

In this case, the ‘tightly coupled technology’ may be a technology inwhich only the power transmission between a single transmitter coil anda single receiver coil (one-to-one power transmission) is available.

As an example of the wireless power transmitting and charging systemapplied to a wireless power transmission network like a local computingenvironment, Korean patent publication No. 2014-0057503 (published onMay 13, 2014) and Korean patent publication No. 2014-0061337 (publishedon May 13, 2014) are published. However, these related arts fail toprovide a clear method for the power control.

DISCLOSURE Technical Problem

An object of the present invention is to provide a wireless powertransmitting and charging system and an improved composition of thewireless power transmitting and charging system.

Technical Solution

A method for transmitting wireless power and operating a powertransmitter of a charge system according to an embodiment includesmaintaining a ping value table where a ping signal condition is mappedto each height of a power receiver, detecting the power receiver byvarying a ping signal according to the ping signal condition recorded inthe ping value table and controlling a charge mode according to amessage received from the power receiver.

A device for transmitting wireless power and a power transmitter of acharge system according to an embodiment includes a memory in which aping value table where a ping signal condition is mapped to each heightof a power receiver is stored, a detecting unit for detecting the powerreceiver by varying a ping signal according to the ping signal conditionrecorded in the ping value table and a charge mode control unit forcontrolling a charge mode according to a message received from the powerreceiver.

Technical Effects

According to an embodiment of the present invention, efficient wirelesspower transmission and charge are available.

In addition, according to an embodiment of the present invention, whencharging wirelessly, it is available to detect a power receiverefficiently without regard to a height of the power receiver, and toperform a wireless charge with an optimized condition.

DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram illustrating constituting elements of awireless power transmission system according to an embodiment of thepresent invention.

FIG. 2 is a block diagram of a wireless power transmitter and a wirelesspower receiver according to an embodiment of the present invention.

FIG. 3 is a detailed block diagram of the wireless power transmitter andthe wireless power receiver according to an embodiment of the presentinvention.

FIG. 4 is a flowchart for describing an operation of a wireless powertransmitter and a wireless power receiver according to an embodiment ofthe present invention.

FIG. 5 is a flowchart for describing operations of a wireless powertransmitter and a wireless power receiver according to anotherembodiment of the present invention.

FIG. 6 is a graph with respect to the time axis of the amount of powerapplied by the wireless power transmitter according to the embodiment ofFIG. 5.

FIG. 7 is a block diagram of a wireless power transmitter and a wirelesspower receiver according to another embodiment of the present invention.

FIG. 8 is a diagram illustrating an example of including two primarycoils.

FIG. 9 is a diagram illustrating an example of including three primarycoils.

FIG. 10 is a detailed block diagram of a power transmitting unit withrespect to a wireless power transmitter according to the embodiment ofFIG. 7.

FIG. 11 is a diagram illustrating an example of a construction of aprimary coil array with respect to a power transmitting unit.

FIG. 12 is a flowchart for describing a control operation of a wirelesspower transmitter.

FIG. 13 is a diagram for describing a composition of a powertransmitting unit according to an embodiment of the present invention.

FIG. 14 is a diagram illustrating an example of a connection relation ofan output terminal of the inverter with the magnetic inductiontransmitting unit 1320 and the magnetic resonance transmitting unitincluded in the power transform unit of FIG. 13.

FIG. 15 illustrates an example of a composition of the magneticinduction transmitting unit and the magnetic resonance transmitting unitof FIG. 13.

FIG. 16 is a diagram for describing a method for controlling the primarycoil array of FIG. 11 according to an embodiment.

FIG. 17 is a diagram for describing a power transfer control algorithmof a wireless power transmitter.

FIG. 18 illustrates a composition example of a power transmitteraccording to an embodiment.

FIG. 19 illustrates an operation method of a power transmitter accordingto an embodiment.

BEST MODE FOR INVENTION

Hereinafter, the embodiments of the present invention are described indetail with reference to the accompanying drawings.

FIG. 1 is a diagram for describing an overall concept of a wirelesspower transmission system.

Referring to FIG. 1, a wireless charge system may transmit each power1-1, 1-2 and 1-n wirelessly to a wireless power transmitter 100 and atleast one wireless power receiver 110-1, 110-2 and 110-n. Moreparticularly, the wireless power transmitter 100 may transmit power 1-1,1-2 and 1-n wirelessly only to the authenticated wireless power receiverthat performs a predetermined authentication procedure.

The wireless power transmitter 100 may form an electrical connectionwith the wireless power receivers 110-1, 110-2 and 110-n. For example,the wireless power transmitter 100 may transmit wireless power in a formof electromagnetic wave to the wireless power receivers 110-1, 110-2 and110-n.

In addition, the wireless power transmitter 100 may perform abi-directional communication with the wireless power receivers 110-1,110-2 and 110-n. In this case, the wireless power transmitter 100 andthe wireless power receivers 110-1, 110-2 and 110-n may process ortransmit and receive packets 2-1, 2-2 and 2-n including a predeterminedframe. The frame is described in more detail below. The wireless powerreceiver may be implemented, particularly, by a mobile communicationterminal, a PDA, a PMP, a smart phone, and so on.

Furthermore, the wireless power transmitter 100 may provide powerwirelessly to a plurality of the wireless power receivers 110-1, 110-2and 110-n. For example, the wireless power transmitter 100 may transmitpower to a plurality of the wireless power receivers 110-1, 110-2 and110-n through the resonance technique. In the case that the wirelesspower transmitter 100 adopts the resonance technique, a distance betweenthe wireless power transmitter 100 and the wireless power receivers110-1, 110-2 and 110-n may be 30 m or shorter, preferably. In addition,the wireless power transmitter 100 adopts the electromagnetic inductiontechnique, a distance between the wireless power transmitter 100 and thewireless power receivers 110-1, 110-2 and 110-n may be 10 m or shorter,preferably.

In addition, the wireless power transmitter 100 may include a displaymeans like a display, and may display a state of each of the wirelesspower receivers 110-1, 110-2 and 110-n based on a message received fromeach of the wireless power receivers 110-1, 110-2 and 110-n.Furthermore, the wireless power transmitter 100 may display a timeexpected until charge of each of the wireless power receivers 110-1,110-2 and 110-n is completed together.

Furthermore, the wireless power transmitter 100 may transmit a controlsignal configured to disable the wireless charge function to each of thewireless power receivers 110-1, 110-2 and 110-n. The wireless powerreceiver that receives the disable control signal of the wireless chargefunction from the wireless power transmitter 100 may disable thewireless charge function.

The wireless power receivers 110-1, 110-2 and 110-n may perform chargeof the battery equipped therein by receiving wireless power from thewireless power transmitter 100. In addition, the wireless powerreceivers 110-1, 110-2 and 110-n may transmit a signal requesting awireless power transmission, information required for a wireless powerreception, wireless power state information or control information ofthe wireless power transmitter 100, and so on to the wireless powertransmitter 100. The information of the transmission signal is describedin more detail below.

In addition, the wireless power receivers 110-1, 110-2 and 110-n maytransmit a message that represents each charge state to the wirelesspower transmitter 100.

FIG. 2 is a block diagram of a wireless power transmitter and a wirelesspower receiver according to an embodiment of the present invention.

Referring to FIG. 2, a wireless power transmitter 200 may include apower transmitting unit 211, a control unit 212 and a communication unit213. In addition, a wireless power receiver 250 may include a powerreceiving unit 251, a control unit 252 and a communication unit 253.

The power transmitting unit 211 may provide power required by thewireless power transmitter 200, and may provide power to the wirelesspower receiver 250 wirelessly. Here, the power transmitting unit 211 mayprovide power in a form of AC waveform, and while providing power in aform of DC waveform, may provide power in a form of AC waveform bytransforming the DC waveform into AC waveform using an inverter. Thepower transmitting unit 211 may be implemented as a form of an embeddedbattery, or may also be implemented as a form of a power receptioninterface, and accordingly, may be implemented as a form of receivingpower from outside and providing the power to another element. It isunderstood to a person skilled in the art that the power transmittingunit 211 is not limited if it is a means to provide the power ofpredetermined AC waveform.

Furthermore, the power transmitting unit 211 may provide AC waveform tothe wireless power receiver 250 as a form of electromagnetic wave. Thepower transmitting unit 211 may further include a loop coil, andaccordingly, may transmit and receive a predetermined electromagneticwave. In the case that the power transmitting unit 211 is implemented asthe loop coil, inductance L of the loop coil may be changeable.Meanwhile, it is understood that power transmitting unit 211 is notlimited if it is a means able to transmit and receive electromagneticwave.

The control unit 212 may control the overall operations of the wirelesspower transmitter 200. The control unit 212 may the overall operationsof the wireless power transmitter 200 by using the algorithm, program orapplication required to control readout from a storing unit (not shown).The control unit 212 may be implemented as a form such as a CPU, amicroprocessor and a mini computer. The detailed operation of thecontrol unit 212 is described in more detail below.

The communication unit 213 may perform a communication in apredetermined technique with the wireless power receiver 250. Thecommunication unit 213 may perform a communication using the Near FieldCommunication (NFC), the Zigbee communication, the infraredcommunication, the visible light communication, and so on with thecommunication unit 253. The communication unit 213 according to anembodiment may perform a communication using the Zigbee communicationtechnique of IEEE802.15.4 scheme. Furthermore, the communication unit213 may use the Carrier Sense Multiple Access with Collision Avoidance(CSMA/CA) algorithm. The composition for the frequency and channelselection used by the communication unit 213 is described in more detailbelow. Meanwhile, the communication technique described above is just anexample, but the present invention is not limited to a specificcommunication technique performed in the communication unit 213.

Meanwhile, the communication unit 213 may transmit a signal for theinformation of the wireless power transmitter 200. Here, thecommunication unit 213 may perform unicast, multicast or broadcast ofthe signal.

The communication unit 213 may receive power information from thewireless power receiver 250. Here, the power information may include atleast one of capacity of the wireless power receiver, battery remains,charge number, use amount and battery ratio. In addition, thecommunication unit 213 may transmit a charge function control signal tocontrol the charge function of the wireless power receiver 250. Thecharge function control signal may be a control signal makes the chargefunction be enabled or disabled by controlling the wireless powerreceiving unit 251 of a specific wireless power receiver 250.

Furthermore, the communication unit 213 may receive a signal from otherwireless power transmitter (not shown), as well as the wireless powerreceiver 250. For example, the communication unit 213 may receive aNotice signal of a frame from other wireless power transmitter.

Meanwhile, in FIG. 2, it is shown that the power transmitting unit 211and the communication unit 213 are implemented as different hardware andthe wireless power transmitter 200 communicates in an out-bandformality, but this is just an example. According to the presentinvention, the power transmitting unit 211 and the communication unit213 are implemented as a single hardware and may perform communicationin an in-band formality.

The wireless power transmitter 200 and the wireless power receiver 250may receive various types of signals, and accordingly, a chargeprocedure may be performed through an admission of the wireless powerreceiver 250 to a wireless power network managed by the wireless powertransmitter 200 and the wireless power transmission and reception. Theprocedure described above is described in more detail below.

In addition, FIG. 2 schematically exemplifies the composition of thewireless power transmitter 200 and the wireless power receiver 250, butFIG. 3 exemplifies a detailed composition of the wireless powertransmitter 200 and the wireless power receiver 250. The detaileddescription is described below.

FIG. 3 is a detailed block diagram of the wireless power transmitter andthe wireless power receiver according to an embodiment of the presentinvention.

Referring to FIG. 3, the wireless power transmitter 200 may include thepower transmitting unit 211, the control unit and the communication unit212 and 213, a driving unit 214, an amplifying unit 215 and a matchingunit 216. The wireless power receiver 250 may include the powerreceiving unit 251, the control unit and the communication unit 252 and253, a rectifying unit 254, a DC/DC converter unit 255, a switching unit256 and a load unit 257.

The driving unit 214 may output a DC power that has a predeterminedvoltage value. The voltage value of the DC power outputted from thedriving unit 214 may be controlled by the control unit and thecommunication unit 212 and 213.

The DC current outputted from the driving unit 214 may be outputted tothe amplifying unit 215. The amplifying unit 215 may amplify the DCcurrent with a predetermined gain. Furthermore, the amplifying unit 215may transform the DC power into AC based on the signal inputted from thecontrol unit and the communication unit 212 and 213. Accordingly, theamplifying unit 215 may output AC power.

The matching unit 216 may perform the impedance matching. For example,by adjusting the impedance seen from the matching unit 216, it may becontrolled such that an output power becomes efficient or high power.The matching unit 216 may include at least one of a coil and acapacitor. The control unit and the communication unit 212 and 213 maycontrol a connection state with at least one of the coil and thecapacitor, and accordingly, may perform the impedance matching.

The power transmitting unit 211 may transmit the inputted AC power tothe power receiving unit 251. The power transmitting unit 211 and thepower receiving unit 251 may be implemented by resonance circuits thathave the same resonance frequency. For example, the resonance frequencymay be determined to be 6.78 MHz. The control unit and the communicationunit 212 and 213 may perform a communication with the control unit andthe communication unit 252 and 253 at the part of the wireless powerreceiver 250.

Meanwhile, the power receiving unit 251 may receive charge power fromthe power transmitting unit 211.

The rectifying unit 254 may rectify the wireless power received in thepower receiving unit 251 into an AC form, for example, may beimplemented as the bridge diode. The DC/DC converting unit 255 mayconvert the rectified power with a predetermined gain. For example, theDC/DC converting unit 255 may convert the rectified power such that thevoltage at an output terminal 259 is 5 V. Meanwhile, at a front terminal258 of the DC/DC converting unit 255, a minimum value and a maximumvalue of the voltage that is available to be applied may bepreconfigured.

The switching unit 256 may connect the DC/DC converting unit 255 and theload unit 257. The switching unit 256 may maintain on/off stateaccording to the control of the control unit 252. The load unit 257 maystore the converted power which is inputted from the DC/DC convertingunit 255 when the switching unit 256 is on state.

FIG. 4 is a flowchart for describing an operation of a wireless powertransmitter and a wireless power receiver according to an embodiment ofthe present invention.

Referring to FIG. 4, a wireless power transmitter 400 may apply a powersource (step, S401). When the power is applied, the wireless powertransmitter 400 may configure an environment.

The wireless power transmitter 400 may enter a Power Save Mode (step,S403). In the Power Save Mode, the wireless power transmitter 400 mayapply each of power beacons 404 and 405 for detecting heterogeneity witheach period. For example, as shown in FIG. 4, the wireless powertransmitter 400 may apply the power beacon for detection, and the sizeof the power value of each of the power beacons 404 and 405 fordetection may be different. One or both of the power beacons 404 and 405may have an amount of power and an application time for driving acommunication unit of a wireless power receiver 450. For example, thewireless power receiver 450 may drive the communication unit by a partor both of the power beacons 404 and 405 for detection, and may performa communication with wireless power transmitter 400. Such state may bereferred to as Null state.

The wireless power transmitter 400 may detect a load change by anarrangement of the wireless power receiver 450. The wireless powertransmitter 400 may enter a low power mode (step, S409). The low powermode may be a mode in which the wireless power transmitter appliesdetection power periodically or aperiodically. Meanwhile, the wirelesspower receiver 450 may drive the communication unit based on the powerreceived from the wireless power transmitter 400 (step, S409).

The wireless power receiver 450 may transmit a Power Transmitter Unit(PTU) searching signal to the wireless power transmitter 400 (step,S410). The wireless power receiver 450 may transmit the PTU searchingsignal as an Advertisement signal based on BLE. The wireless powerreceiver 450 may transmit the PTU searching signal periodically oraperiodically, and may transmit it until receiving a Power Receiver Unit(PRU) response signal from the wireless power transmitter 400 or apreconfigured time has come.

When the PTU searching signal is received from the wireless powerreceiver 450, the wireless power transmitter 400 may transmit the PRUresponse signal (step, S411). Here, the PRU response signal mayestablish a connection between the wireless power transmitter 400 andthe wireless power receiver 450.

The wireless power receiver 450 may transmit a PRU static signal (step,S412). Here, the PRU static signal may be a signal indicating a state ofthe wireless power receiver 450, and may request an admission to awireless power network which is managed by the wireless powertransmitter 400.

The wireless power transmitter 400 may transmit a PTU static signal(step, S413). The PTU static signal transmitted by the wireless powertransmitter 400 may be a signal indicating a capability of the wirelesspower transmitter 400.

When the wireless power transmitter 400 and the wireless power receiver450 transmit and receive the PRU static signal and the PTU staticsignal, the wireless power receiver 450 may transmit a PRU dynamicsignal periodically (steps, S414 and S415).

The PRU dynamic signal may include at least one type of parameterinformation which is measured in the wireless power receiver 450. Forexample, the PRU dynamic signal may include voltage information at arear part of the rectifying unit of the wireless power receiver 450. Astate of the wireless power receiver 450 may be referred to as Bootstate.

The wireless power transmitter 400 may enter the power transmission mode(step, S416), and the wireless power transmitter 400 may transmit a PRUcommand signal, which is a command signal for the wireless powerreceiver 450 to perform charge (step, S417). In the power transmissionmode, the wireless power transmitter 400 may transmit charge power.

The PRU command signal transmitted by the wireless power transmitter 400may include information for enabling/disabling and information forpermitting charge of the wireless power receiver 450. The PRU commandsignal may be transmitted when the wireless power transmitter 400changes a state of the wireless power receiver 450 or may be transmittedwith a preconfigured period (e.g., period of 250 ms). The wireless powertransmitter 400 may change a configuration according to the PRU commandsignal, and may transmit the PRU dynamic signal for reporting a state ofthe wireless power transmitter 400 (steps, S418 and S419). The PRUdynamic signal transmitted by the wireless power receiver 450 mayinclude at least one of voltage, current, wireless power receiver stateand temperature information. The state of the wireless power receiver450 may be referred to as on state.

The wireless power receiver 450 may perform charge by receiving the PRUcommand signal. For example, in the case that the wireless powertransmitter 400 has a power enough to charge the wireless power receiver450, the wireless power transmitter 400 may transmit the PRU commandsignal. Meanwhile, the PRU command signal may be transmitted wheneverthe charge state is changed. For example, the PRU command signal may betransmitted when it may be transmitted in every 250 ms or a parameter ischanged. The PRU command signal may be configured to be transmittedwithin a preconfigured threshold time (e.g., within 1 second) even inthe case that a parameter is not changed.

Meanwhile, the wireless power receiver 450 may detect an occurrence ofan error. The wireless power receiver 450 may transmit a warning signalto the wireless power transmitter 400 (step, S420). The warning signalmay be transmitted as a PRU dynamic signal or a PRU warning signal. Forexample, wireless power receiver 450 may reflect an error situation tothe PRU warning information field in Table 4 and transmit it to thewireless power transmitter 400. Otherwise, the wireless power receiver450 may transmit a single warning signal indicating an error situationto the wireless power transmitter 400. When the wireless powertransmitter 400 receives the PRU warning signal, the wireless powertransmitter 400 may enter a Latching fault mode (step, S422). Thewireless power receiver 450 may enter a Null state (step, S423).

FIG. 5 is a flowchart for describing operations of a wireless powertransmitter and a wireless power receiver according to anotherembodiment of the present invention.

The control method of FIG. 5 is described in more detail by referring toFIG. 6. FIG. 6 is a graph with respect to the time axis of the amount ofpower applied by the wireless power transmitter according to theembodiment of FIG. 5.

Referring to FIG. 5, the wireless power transmitter may initiate adriving (step, S501). Furthermore, the wireless power transmitter mayreset an initial configuration (step, S503). The wireless powertransmitter may enter the power save mode (step, S505). Here, the powersave mode may correspond to a duration in which the wireless powertransmitter applies heterogeneous power of which amount of power isdifferent to a power transmitting unit. For example, the wireless powertransmitter may correspond to duration in which second detected powers601 and 602 and third detected powers 611, 612, 613, 614 and 615 to thepower transmitting unit. Here, the wireless power transmitter may applythe second detected powers 601 and 602 with a second periodperiodically, and in the case of applying second detected powers 601 and602, the wireless power transmitter may apply it during a secondduration.

The wireless power transmitter may apply the third detected powers 611,612, 613, 614 and 615 with a third period periodically, and in the caseof applying the third detected powers 611, 612, 613, 614 and 615, thewireless power transmitter may apply it during a third duration.Meanwhile, although it is shown that each power value of the thirddetected powers 611, 612, 613, 614 and 615 is different, each powervalue of the third detected powers 611, 612, 613, 614 and 615 may bedifferent or the same.

After outputting the third detected power 611, the wireless powertransmitter may output the third detected power 612 that has the sameamount of power. In the case that the wireless power transmitter outputsthe third detected powers of which size is the same, the amount of powerof the third detected power may have the amount of power that may detectthe smallest wireless power receiver, for example, the wireless powerreceiver of category 1.

After outputting the third detected power 611, the wireless powertransmitter may output the third detected power 612 that has differentamount of power. In the case that the wireless power transmitter outputsthe third detected powers of which sizes are different, each of theamounts of power of the third detected power may be an amount of powerthat is able to detect the wireless power receiver of category 1 to 5.For example, the third detected power 611 may have the amount of powerthat is able to detect the wireless power receiver of category 5, andthe third detected power 612 may have the amount of power that is ableto detect the wireless power receiver of category 3. And, the thirddetected power 613 may have the amount of power that is able to detectthe wireless power receiver of category 1.

Meanwhile, the second detected powers 601 and 602 may be the power thatis able to drive the wireless power receiver. More particularly, thesecond detected powers 601 and 602 may have the amount of power that isable to drive a control unit and a communication unit of the wirelesspower receiver.

The wireless power transmitter may apply the second detected powers 601and 602 and the third detected powers 611, 612, 613, 614 and 615 to thepower receiving unit with the second period and the third period,respectively. In the case that the wireless power receiver is disposedon the wireless power transmitter, the impedance seen from a point ofthe wireless power transmitter may be changed. The wireless powertransmitter may detect a change of the impedance while the seconddetected powers 601 and 602 and the third detected powers 611, 612, 613,614 and 615 are applied. For example, the wireless power transmitter maydetect a change of the impedance while the third detected power 615 isapplied. Accordingly, the wireless power transmitter may detect anobject (step, S507). In the case that an object is not detected (step,S507—N), the wireless power transmitter may maintain the power save modein which heterogeneous power is periodically applied (step, S505).

Meanwhile, in the case that impedance is changed and an object isdetected (step, S507—N), the wireless power transmitter may enter thelow power mode. Here, the low power mode is a mode in which a drivingpower is applied, which has an amount of power that the wireless powertransmitter is able to drive the control unit and the communication unitof the wireless power receiver. For example, as shown in FIG. 6, thewireless power transmitter may apply the driving power 620 to the powertransmitting unit. The wireless power receiver may drive the controlunit and the communication unit by receiving the driving power 620. Thewireless power receiver may perform a communication based on apredetermined technique with the wireless power transmitter based on thedriving power 620. For example, the wireless power receiver may transmitand receive data required for authentication, and may subscribe to awireless power network managed by the wireless power receiver based onit. However, in the case that a foreign object, not the wireless powerreceiver, is disposed, data transmission and reception may not beperformed. Accordingly, the wireless power transmitter may determinewhether the disposed object is a foreign object (step, S511). Forexample, in the case that the wireless power transmitter is unable toreceive a response from an object during a preconfigured time, thewireless power transmitter may determine the object to be a foreignobject.

In the case that it is determined to be a foreign object (step, S511—Y),the wireless power transmitter may enter a Latching fault mode. Forexample, the wireless power transmitter may apply first powers 631 to634 with a first period periodically. The wireless power transmitter maydetect impedance change while the wireless power transmitter applies thefirst powers. For example, in the case that a foreign object is removed,a change of impedance may be detected, and the wireless powertransmitter may determine that a foreign object is removed. Otherwise,in the case that a foreign object is not removed, the wireless powertransmitter is unable to detect a change of impedance, and the wirelesspower transmitter may determine that a foreign object is not removed. Inthe case that a foreign object is not removed, the wireless powertransmitter may output at least one of a lamp light and a warning soundand notify the current state of the wireless power transmitter to be inan error state. Accordingly, the wireless power transmitter may includean output unit that outputs at least one of a lamp light and a warningsound.

In the case that a foreign object is not removed (step, S515—N), thewireless power transmitter may maintain the Latching fault mode (step,S513). Meanwhile, in the case that a foreign object is removed (step,S515—Y), the wireless power transmitter may enter the power save modeagain (step, S517). For example, the wireless power transmitter mayapply second powers 651 and 652 and third powers 661 to 665.

Meanwhile, in relation to FIGS. 5 and 6, in the case that the impedancechange owing to an arrangement of the wireless power receiver is not sogreat, it may be hard to detect the wireless power receiver.

FIG. 7 is a block diagram of a wireless power transmitter and a wirelesspower receiver according to another embodiment of the present invention.

Referring to FIG. 7, a wireless power transmitter 700 may include asystem control unit 710 and at least one power transmitting unit 720 and730, and the power transmitting units 720 and 730 may include powertransform units 721 and 731 and control units 723 and 733. In addition,a wireless power receiver 750 may include a power receiving unit 751 anda load unit 755, and the power receiving unit 751 may include a powerpickup unit 752 and a communication and control unit 753.

The power transform units 721 and 731 may transform electrical power towireless power, and may transmit the wireless power to the power pickupunit 752 included in a receiving unit 751 of the at least one wirelesspower receiver 750. The power transform units 721 and 731 may include aprimary coil of the magnetic induction technique for transmittingwireless power.

The power pickup unit 752 may receive wireless power from the powertransform units 721 and 731 and may transform the received wirelesspower to electrical power, and may include a secondary coil of themagnetic induction technique for receiving wireless power. For example,the power transform units 721 and 731 and the power pickup unit 752 maytransmit and receive wireless power by maintaining the primary coil andthe secondary coil in at least one of a horizontal arrangement state anda vertical arrangement state. The primary coil may be a coil of thewire-wound type and a coil array including at least one coil, and mayform a coreless resonance transformer part together with the secondarycoil.

Meanwhile, the wireless power transmitter 700 may further include aninterface surface (not shown) of a flat surface shape to transmitwireless power. At an upper part of the interface surface, at least onewireless power receiver 750 may be placed, and a primary coil may beprovided at a lower part of the interface surface. In this case, a smallvertical spacing may be formed between the primary coil mounted at thelower part of the interface surface and the secondary coil of thewireless power receiver 750 located at the upper part of the interfacesurface, and accordingly, the inductive coupling may be establishedbetween the primary coil and the secondary coil. Hereinafter, theprimary coil is described in detail.

FIG. 8 is a diagram illustrating an example of including two primarycoils and FIG. 9 is a diagram illustrating an example of including threeprimary coils.

Referring to FIG. 8, two primary coils may be coils of the wire-woundtype, and the coil of the wire-wound type may be constructed by Litzwire including 115 strands and a diameter of 0.08 mm. In addition, thetwo primary coils may have Racetrack-like shape, and may be constructedas a single layer. Furthermore, parameters of the two primary coils mayhave d_(o) and d_(h), and herein, d_(o) may be an outer diameter of theprimary coil and d_(h) may be a distance between centers of the twoprimary coils.

Referring to FIG. 9, the three primary coils may be constructed by Litzwire including 105 strands and a diameter of 0.08 mm. In addition, thethree primary coils may have a rectangular shape, and may be constructedas a single layer. Furthermore, parameters of the three primary coilsmay have d_(oe) and d_(oo), and herein, d_(oe) may be a distance betweena center of a first primary coil and a center of a second primary coil,and d_(oo) may be a distance between a center of the first primary coiland a center of a third primary coil.

Referring to FIG. 7 again, the communication and control unit 723 and733 may perform a communication with at least one power receiving unit752. In addition, the communication and control unit 723 and 733 mayreceive a request message for required wireless power from the powerreceiving unit 752, and accordingly, the communication and control unit723 and 733 may control the power transform unit 721 such that therequested wireless power requested is transmitted to the power receivingunit 752.

The power pickup unit 752 may receive wireless power from the powertransform unit 721, and the load unit 755 may charge a battery byloading the received wireless power. The communication and control unit753 may perform a communication with transmitting units 720 and 730, andmay control such that wireless power is received from the transmittingunits 720 and 730. Hereinafter, by referring to FIG. 10, a detailedconstruction of the power transmitting units 720 and 730 is described.

FIG. 10 is a detailed block diagram of a power transmitting unit withrespect to a wireless power transmitter according to the embodiment ofFIG. 7.

Referring to FIG. 10, the power transmitting units 720 and 730 mayinclude the communication and control unit 721 and the power transformunit 723, and the power transform unit 723 may include an inverter 723a, an impedance matching unit 723 b, a sensing unit 723 c, a multiplexer723 d and a primary coil array 723 e.

In the power transform unit 723, the inverter 723 a may transform adirect current (DC) current an alternating current (AC) waveform, andthe impedance matching unit 723 b may match a connection between aresonance circuit and the primary coil array 723 e. In addition, thesensing unit may detect and monitor the current and the voltage betweenthe resonance circuit and the primary coil array 723 e, and themultiplexer 723 d may connect/disconnect the primary coil properlyaccording to a position of the power receiving unit 751.

The communication and control unit 721 may receive a request message forwireless power from the power receiving unit 751, and may control aconnection for a proper primary coil array through the multiplexer 723d. In addition, the communication and control unit 721 may control theinverter 723 a such that an amount of wireless power is adjusted byexecuting a power control algorithm and protocols, and may control theprimary coil array 723 e such that the wireless power is transmitted tothe power receiving unit 751. Hereinafter, by referring to FIG. 11, theprimary coil array 723 e of the power transmitting units 720 and 730 isdescribed.

FIG. 11 is a diagram illustrating an example of a construction of aprimary coil array with respect to a power transmitting unit.

In FIG. 11, (a) is an example of depicting an upper single layer of aprimary coil array, (b) is an example of depicting a side of a primarycoil array, and (c) is an example of depicting an upper layer of aprimary coil array.

The primary coil may be formed of a circular shape and may include asingle layer, and the primary coil array may include a plurality ofprimary coil layers that has hexagonal lattice areas.

Referring to FIG. 11, primary coil array parameters may include d_(o),d_(i), d_(c), d_(a), d_(h), t₂ and t₃. d_(o) is an outer diameter of theprimary coil layer, d_(i) is an inner diameter of the primary coillayer, d_(c) is a thickness of the primary coil layer, d_(a) is athickness of the primary coil array, d_(h) is a distance between centersof the neighboring primary coil layers, t₂ is an offset of the secondprimary coil layer array and t₃ is an offset of the third primary coillayer array.

Referring to FIG. 7 again, the system control unit 710 may control awireless power transmission with at least one wireless power receiver750. Accordingly, the wireless power transmitter 700 may transmitwireless power to a plurality of wireless power receiver (not shown).Hereinafter, by referring to FIG. 12, the system control unit 710 thatperforms a control operation of the wireless power transmitter 700 isdescribed in detail.

FIG. 12 is a flowchart for describing a control operation of a wirelesspower transmitter.

Referring to FIG. 12, the control operation of the wireless powertransmitter may include a step of selection, a step of ping, a step ofidentification and configuration and a step of power transfer.

The step of selection may monitor an interface surface for positioningand removing the wireless power receiver. For example, the step ofselection may detect and monitor at least one wireless power receiverexisted in a free position, and may distinguish an entity (e.g., aforeign object, a key or a coin, etc.) which is not the wireless powerreceiver.

In addition, in the case that the information of the wireless powerreceiver is in short, the step of selection may select the relatedinformation by performing repeatedly the step of ping and the step ofidentification and configuration. Furthermore, the step of selection mayselect a primary coil to transmit wireless power to the wireless powerreceiver. In addition, the step of selection may switch to an idle modein the case that the primary coil is not selected.

The step of ping may perform a digital ping, and may wait until aresponse to the wireless power receiver is received. In addition, thestep of ping may extend the digital ping or maintain the level of thedigital ping in the case that the wireless power receiver is detected.Furthermore, in the case that the digital ping is not extended, the stepof ping may return to the step of selection again.

The step of identification and configuration may identify the selectedwireless power receiver, and obtain the wireless power amountconfiguration information requested by the wireless power receiver. Inaddition, the step of identification and configuration

The step of power transfer may transfer wireless power amount requestedto the identified wireless power receiver, and may adjust the current ofthe primary coil based on the control data. In addition, when atransmission for the wireless power amount requested to the identifiedwireless power receiver is completed, the step of power transfer maystop the wireless power transmission for the identified wireless powerreceiver.

FIG. 13 is a diagram for describing a composition of a powertransmitting unit according to an embodiment of the present invention.

A power transmitting unit 1300 shown in FIG. 13 may include a powertransform unit 1310 including an inverter, a magnetic inductiontransmitting unit 1320 for transmitting power in the magnetic inductiontechnique and a magnetic resonance transmitting unit 1330 fortransmitting power in the magnetic resonance technique.

The magnetic induction transmitting unit 1320 and the magnetic resonancetransmitting unit 1330 may be turned on/off in the time division methodor may be turned on/off simultaneously. Accordingly, the powertransmitting unit 1300 may transmit power to a wireless power receivingdevice in the magnetic induction technique and to a wireless powerreceiving device in the magnetic resonance technique simultaneously.

FIG. 14 is a diagram illustrating an example of a connection relation ofan output terminal of the inverter with the magnetic inductiontransmitting unit 1320 and the magnetic resonance transmitting unit 1330included in the power transform unit 1310 of FIG. 13.

Referring to FIG. 13 and FIG. 14, the power transmitting unit 1300 maycontrol a first switch 1410, a second switch 1420 and a third switch1430, and may operate in a magnetic induction transmission mode, amagnetic resonance transmission mode and a hybrid mode. In this case,the hybrid mode may be a mode of performing the power transmission inthe magnetic induction technique and the power transmission in themagnetic resonance technique.

The wireless power transmitter may perform a communication with awireless power receiving device or may measure a change of impedance todetermine an operational mode, and in the case that the type of thewireless power receiving device is not clear, the wireless powertransmitter may operate in the hybrid mode.

A power supplying unit 1311 applies DC voltage to a switching unit 1315,and a driving unit 1313 controls the switching unit 1315 and outputs ACvoltage to an inverter output terminal 1401.

The magnetic induction transmitting unit 1320 of FIG. 13 may include afirst capacitor 1321 and a first inductor 1323.

The magnetic resonance transmitting unit 1330 of FIG. 13 may include asecond capacitor 1331 and a second inductor 1333.

An end of the first switch 1410 may be connected to the inverter outputterminal 1401, and another end may be connected to the first capacitor1321.

An end of the second switch 1420 may be connected to the inverter outputterminal 1401, and another end may be connected to the second capacitor1331.

In the magnetic induction transmission mode, the first switch 1410 maybe turned on and the second switch 1420 and the third switch 1430 may beturned off.

In the first magnetic resonance transmission mode, the first switch 1410may be turned off and the second switch 1420 may be turned on.

In the second magnetic resonance transmission mode, the first switch1410 may be turned on and the second switch 1420 may be turned on.

At this time, in the case that the power transmitting unit 1300 turns onthe third switch 1430, the first switch is always turned on and thesecond switch 1420 is always turned off.

In the case that the third switch 1430 is turned on in the magneticresonance transmission mode, the second capacitor 1331 and the secondinductor 1333 forms a closed loop. In this case, the closed loop may bereferred to as a resonator. In the second magnetic resonancetransmission mode, energy may be induced from the first inductor 1323 tothe second inductor 1333, and may be transferred to a wireless powerreceiving device through the resonator.

In the second magnetic resonance transmission mode, since the secondcapacitor 1331 and the second inductor 1333 operate as a resonator, thesecond capacitor 1331 and the second inductor 1333 does not influence onthe inherent resonance frequency of the entire system. Accordingly, inthe second magnetic resonance transmission mode, energy may betransferred to the wireless power receiving device with higherefficiency than that of the first magnetic resonance transmission mode.Accordingly, the second switch 1320 shown in FIG. 14 may be removed.

The power transmitting unit 1300 may operate as the hybrid mode byturning on/off the first switch 1410 and the second switch 1420 in thetime division method. In addition, the power transmitting unit 1300 mayoperate as the hybrid mode by turning on/off the third switch 1430 inthe state that the first switch 1410 is continuously turned on.

Meanwhile, in FIG. 14, the first capacitor 1321 and the first inductor1323 may be an equivalent circuit of an induction coil, and may also bereferred to as a first capacitance and a second inductance,respectively. Likewise, the second capacitor 1331 and the secondinductor 1333 may be an equivalent circuit of a resonance coil, and mayalso be referred to as a second capacitance and a second inductance,respectively.

FIG. 15 illustrates an example of a composition of the magneticinduction transmitting unit 1320 and the magnetic resonance transmittingunit 1330 of FIG. 13.

Referring to FIG. 15, the magnetic induction transmitting unit 1320 mayinclude a single coil or a coil array 1520, and the magnetic resonancetransmitting unit 1330 may include a resonance coil 1530 of a shape ofembracing the coil array 1520.

The coil array 1520 may include a plurality of coil cells 1521, 1523,1525 and 1527. Of course, the coil array 1520 may include a plurality ofprimary coils constructed as FIG. 9 or FIG. 11.

In the magnetic induction transmission mode, depending on the requiredpower amount, only a part of a plurality of the coil cells may be turnedon or all of a plurality of the coil cells may be turned on.

In addition in the case that the coil array 1520 includes a plurality ofthe coil cells, in the second magnetic resonance transmission mode,depending on the required power amount, only a part of a plurality ofthe coil cells may be turned on or all of a plurality of the coil cellsmay be turned on.

FIG. 16 is a diagram for describing a method for controlling the primarycoil array of FIG. 11 according to an embodiment.

As described in FIG. 12, after the step of identification andconfiguration, the wireless power transmitter may operate in the step ofpower transfer.

At this time, in the step of power transfer, in the case that a newwireless power receiver appears or a foreign object is existed, a methodis required for controlling the primary coil array.

Referring to FIG. 16, a primary coil array 1600 according to anembodiment may include a plurality of primary coils and a plurality ofsensors 1640.

In this case, the sensor 1640 may be a pressure sensor or a temperaturesensor. In other words, the primary coil array 1600 may also include aplurality of pressure sensors and a plurality of temperature sensors.

The sensor 1640 may be provided on a plurality of positions of theprimary coil array 1600. Accordingly, the wireless power transmitter maydetect a new object on a specific position by a pressure change and maydetect temperature change of a specific position through the sensor1640.

For example, in the “Power Transfer” step for transmitting power to afirst wireless power receiving device 1610 in a first time duration,when a new wireless power receiving device 1620 is located on a specificposition of the primary coil array 1600, the sensing value of thepressure sensor in the corresponding position may be changed.

At this time, the wireless power transmitter may stop the “PowerTransfer” step, and may operate in the step of identification andconfiguration.

Meanwhile, in the “Power Transfer” step, a foreign object 1630 may belocated on the primary coil which is operating or on the primary coilwhich is not operating.

At this time, the wireless power transmitter may detect the temperatureon a specific position is increased through the temperature sensor. Inthe case that the temperature is increased over a preconfiguredthreshold temperature, the primary coils (e.g., four coils around thetemperature sensor) that are driven around the corresponding temperaturesensor may be turned off and the operation may be stopped.

In addition, even in the case that the primary coils around thetemperature sensor that detects the temperature increase are turned off,when temperature is not decreased under the threshold value orincreased, an operation of the entire primary coil array may be stoppedtemporarily. Furthermore, in order to detect a foreign object, the“Power Transfer” step is stopped, and operated in the step ofidentification and configuration.

In an embodiment, the temperature sensor may be provided only in threeparts or four parts of the entire primary coil array 1600. In the casethat three temperature sensors are provided, using the temperaturedifference values measured in the three sensors, a position of the cellmay be determined of which the temperature increases over a thresholdvalue.

For example, when a first temperature sensor, a second temperaturesensor and a third temperature sensor are arranged in a triangle shapeand the respective sensed values are A, B and C, measurement valuesmeasured in advance are stored in a table according to A-B, B-C and C-Avalue and the absolute value thereof. When A-B has the greatest value, Ais greater than B and greater than a threshold value by a predeterminedvalue, the primary coils around A may be turned off. Otherwise, it isalso available to configure that the cells between A and C which areapart from B by a specific distance are turned off in the case that A is25, B is 24.5 and C is 24.6.

Meanwhile, the power transmittable per each primary coil included in theprimary coil array 1600 may be limited owing to temperature increase,electromagnetic wave problem, and so on. Accordingly, in order totransfer power to the wireless power receiving device, the wirelesspower transmitter may determine at least one primary coil to drive, andmay initiate the power transmission only in the case that the maximumtransmission power amount of the first coil to drive is greater than therequested power amount of the wireless power receiving device.

For example, the wireless power transmitter may identify a position andthe requested power amount P_(request) of the wireless power receivingdevice through a communication, and may calculate the transmittablepower amount P_(sum) of the entire primary coils to drive on thecorresponding position. In this case, the number of the primary coils todrive may be limited to a preconfigured number per wireless powerreceiving device. The wireless power transmitter may turn on thecorresponding primary coils only in the case that P_(sum) is greaterthan P_(request).

FIG. 17 is a diagram for describing a power transfer control algorithmof a wireless power transmitter.

The power transfer control of a wireless power transmitter may beprogressed by using Proportional Integral Differential (PID) algorithm.The example shown in FIG. 17 represents an example of the PID algorithm.

In the wireless power transmission system in the magnetic inductiontechnique, examples of the PID parameters for controlling an operatingfrequency are as represented in Table 1, and examples of the PIDparameters for controlling a duty cycle are as represented in Table 2.

TABLE 1 Parameter Symbol Value Unit Proportional gain K_(p) 10 mA⁻¹Integral gain K_(i) 0.05 mA⁻¹ms⁻¹ Derivative gain K_(d) 0 mA⁻¹msIntegral term limit M_(I) 3,000 N.A. PID output limit M_(PID) 20,000N.A.

TABLE 2 Parameter Symbol Value Unit Proportional gain K_(p) 10 mA⁻¹Integral gain K_(i) 0.05 mA⁻¹ms⁻¹ Derivative gain K_(d) 0 mA⁻¹msIntegral term limit M_(I) 3,000 N.A. PID output limit M_(PID) 20,000N.A. Scaling factor S_(v) −0.01 %

In the step of power transfer, the wireless power transmitter maycontrol the current of the primary coil based on the control data. Inthis case, the current control of the primary coil may be performedbased on the PID algorithm.

In FIG. 17, index j=1, 2, 3, . . . represents sequences “Control ErrorPackets” and “Control Error Packet” represents a message that thewireless power transmitter receives from the wireless power receivingdevice in the step of power transfer.

When the wireless power transmitter receives j^(th) Control ErrorPacket, the wireless power transmitter may calculate a new primary cellcurrent t_(d) ^((j)) as Equation 1.

$\begin{matrix}{t_{d}^{(j)} = {t_{a}^{({j - 1})} \cdot \lbrack {1 + \frac{c^{(j)}}{128}} \rbrack}} & \lbrack {{Equation}\mspace{14mu} 1} \rbrack\end{matrix}$

Herein, c^((j)) represents a control error value contained in the jthcontrol error packet, and t_(a) ⁽⁰⁾ represents the current supplied tothe primary coil initially in the step of power transfer.

The wireless power transmitter may calculate the difference of the newprimary cell current and an actual primary cell current as representedin Equation 2.

e ^((j,i)) =t _(d) ^((j)) −t _(a) ^((j,i-1))  [Equation 2]

Herein, t_(a) ^((j,i-1)) represents the primary cell current determinedin the i−1^(th) iteration of the loop, and t_(a) ^((j,0)) represents anactual primary cell current in the start of the loop. Index i=1, 2, . .. i_(max) represents an iteration number of the PID algorithm loop.

The wireless power transmitter may calculate the Proportional term,Integral term and the Derivative term as represented in Equation 3.

$\begin{matrix}{{P^{({j,i})} = {K_{P} \cdot e^{({j,i})}}}{I^{({j,i})} = {I^{({j,{i - 1}})} + {K_{i} \cdot e^{({j,i})} \cdot t_{inner}}}}{D^{({j,i})} = {K_{d} \cdot \frac{e^{({j,i})} - e^{({j,{i - 1}})}}{t_{inner}}}}} & \lbrack {{Equation}\mspace{14mu} 3} \rbrack\end{matrix}$

Herein, K_(p) is a proportional gain, K₁ is an integral gain, K_(d) is aderivative gain, and t_(inner) represents a time required for performingthe PID algorithm loop.

The wireless power transmitter may calculate the summation of theProportional term, Integral term and the Derivative term as representedin Equation 4.

PID^((j,i)) =P ^((j,i)) +I ^((j,i)) +D ^((j,i))  [Equation 4]

In the calculation of Equation 4, the wireless power transmitter shouldlimit the summation PID^((j,i)).

The wireless power transmitter should calculate a new value of thecontrolled variable as represented in Equation 5.

v ^((j,i)) =v ^((j,i-1)) −S _(v)·PID^((j,i))  [Equation 5]

Herein, S_(v) is a scaling factor dependent upon the controlledvariable.

The new value of the controlled variable is transferred to a powerconversion unit. The new value of the controlled variable may be used asa limitation width for controlling current of the primary coil.

According to an embodiment, the wireless power transmitter may changethe value of “PID output limit” depending on the number of coils drivenamong the coils included in the primary coil array.

For example, the wireless power transmitter may increase the value of“PID output limit” as the number of cells driven is increased, and maydecrease the value of “PID output limit” as the number of cells drivenis decreased.

Accordingly, by adjusting the maximum output power of each of coils inthe cell, it is available to protect the wireless power transmitter andstable power transmission is available.

In addition, according to an embodiment, the wireless power transmittermay restrict the voltage and the duty used for the power controldepending on the number of cells driven.

The wireless power transmitter may restrict the power inputted to theprimary coil array depending on the number of driven coils among thecoils included in the primary coil array.

In addition, the wireless power transmitter may restrict the outputpower of the inverter depending on the number of driven coils among thecoils included in the primary coil array.

FIG. 3 to FIG. 7 are descriptions to the description with respect to thetechnique for transmitting power in the magnetic resonance technique,and FIG. 8 to FIG. 12 illustrate the technique for transmitting power inthe magnetic induction technique. The example of transmitting power inthe magnetic resonance technique is described in the prior art 4 indetail. And, FIG. 13 to FIG. 17 illustrate the hybrid technique.

In FIG. 8 to FIG. 12, the magnetic induction technique may be applied toa mouse pad independently from a main device in a local computingenvironment and may be used for transferring power to a mouse on themouse pad.

FIG. 18 illustrates a composition example of a power transmitteraccording to an embodiment.

Referring to FIG. 18, a power transmitter 1800 includes a powertransmitting unit 1810, a memory 1820 and a detecting unit 1830 and acharge mode control unit 1840.

In this case, the power transmitting unit 1810 may include a powertransform unit (not shown) and a coil (not shown).

The memory 1820 stores a ping value table where a ping signal conditionis mapped to each height of a power receiver.

In addition, the memory 1820 may also store a look-up table in which anoptimized value of the driving condition mapped to the ping signalcondition for each height of a power receiver is recorded.

The ping signal condition may be at least one of a frequency of the pingsignal collected in each height, a voltage level of the ping signal anda duty ratio of the ping signal.

The detecting unit 1830 detects the power receiver by varying the pingsignal depending on the ping signal condition recorded in the ping valuetable.

The detecting unit 1830 stores the ping signal condition successful indetecting the power receiver, and configures the ping signal conditionsuccessful in detecting the power receiver as an initial value forvarying the ping signal.

In this case, the initial driving condition mapped to the ping signalcondition may be identical to the ping signal condition successful indetecting the power receiver.

In addition, the initial driving condition mapped to the ping signalcondition may be at least one of a driving frequency for wirelesscharge, a voltage level and a constant value of the ProportionalIntegral Differential (PID) algorithm.

The constant value of the PID algorithm may be at least one of theProportional gain, the Integral gain and the Derivative gain of Table 1,for example.

The charge mode control unit 1840 may control a charge mode according toa message received from the power receiver.

In this case, the control of the charge mode may include startingcharge, ending charge and maintaining a current state.

The charge mode control unit 1840 may identify the initial drivingcondition mapped to the ping signal condition successful in detectingthe power receiver, and may configure the initial driving condition asan initial value of the driving frequency and the voltage level forwireless charge that corresponds to the initial driving condition.

The charge mode control unit 1840 may perform a driving conditionvariable procedure that varies at least one of the driving frequency andthe voltage level, and depending on whether to improve the powertransmission efficiency, may terminate the driving condition variableprocedure or may continue the driving condition variable procedure.

FIG. 19 illustrates an operation method of a power transmitter accordingto an embodiment.

Referring to FIG. 19, in step 1910, a power transmitter maintains theping value table where the ping signal condition is mapped to eachheight of a power receiver.

The power transmitter (transmitting device or also referred to as Tx) ofthe wireless power transmission and the charge system has a structure inwhich charge is restricted depending on a charge distance (Z axis orheight). Accordingly, it may be implemented that the charge is performedwithout regard to the height of the power receiver (also referred to asRx) using digital ping.

In order to generate a ping value table, through the collection offrequency/duty value of the digital ping for each height, thefrequency/duty value of which charge efficiency and the like is goodshould be determined in each height.

Accordingly, by measuring it for a few times or dozens of time in eachheight, the digital ping frequency/duty value for each height may beoptimized.

The selection of the collected frequency/duty is to select thefrequency/duty in which charge is performed well for each height whilethe frequency/duty in which charge is performed well is not overlappedwith the collected data. In this case, it may be selected such that thefrequency/duty is not overlapped for each height.

The ping tabling of the selected frequency/duty combination may bereferred to as a step of ping tabling so as to find the frequency/dutycombination in accordance with each height in the fastest without regardto a height.

In step 1920, the power transmitter detects a power receiver by varyingthe ping signal according to the ping signal condition recorded in theping value table.

In order to determine whether there is a power receiver through thedigital ping, the power transmitter may apply current to the coil of Txand make Rx receive a ping signal, and accordingly, may receive a chargestart message or a charge end message from Rx.

In the case that Tx tries the digital ping, when a receiver is existedon Tx, the receiver may transmit the charge start message or the chargeend message to Tx, and according to these messages, Tx may determinewhether to perform wireless charge.

In the case that a message is not received within a predetermined timewith respect to the digital pin of Tx, Tx brings the next ping data fromthe ping value table in order to prepare the next ping.

In step 1930, the power transmitter controls a charge mode according tothe message received from the power receiver.

In the case that the received message is the “charge start message”, Txhands over the process to the next step in order to try wireless charge.Later, Tx controls wireless charge power by receiving a power controlmessage transmitted from Rx.

In the case that the received message is the “charge end message”, Txstops a wireless charge trial, and stops the digital ping trial untilthe Rx receiver on the Tx coil is removed.

Using the embodiments of the present invention, there is an effect thata charging distance becomes flexible. Accordingly, even in the case thata user installs Tx under a desk or a table irrespective of the thicknessof the desk or the table, the wireless charge may be performed smoothly.

Meanwhile, it is also available to detect an object by activelycontrolling duty of a ping signal.

That is, in the case that an object is detected through varying a dutyratio of a ping signal, the object detection may be tried by varying afrequency of the ping signal. In this case, the ping signal conditionsuccessful in detecting an object may be configured as an initial valueof the next ping signal.

In this case, by accumulating the ping signal conditions successful indetecting an object, in the case that an object is detected in the pingsignal condition for more than a few times, it is also available to setthe ping signal initial value as the corresponding ping signalcondition.

In an embodiment, a ping signal condition for detecting a power receivermay be any one of a frequency, a duty ratio and a power level.

For example, it is available to vary the frequency and the voltage levelsimultaneously, or vary the frequency and the duty simultaneously.

Since a resonant point may be changed depending on a height of the powerreceiver, it may be available to detect the power receiver through afrequency control.

As such, by actively varying various ping signal conditions, the successrate of detecting an object may be increased.

The driving condition varying procedure that varies at least one of adriving frequency and a voltage level may be performed for the purposeof increasing the power transmission efficiency after an initial drivingcondition is determined.

For example, in the case that the power transmission efficiency iscalculated by varying the frequency by a predetermined value and thedriving condition varying procedure is progressed in a direction thatthe power transmission efficiency is improved, after the frequencyreaches to the value of which the power transmission efficiency is nomore improved by varying the frequency continually, it is available totransmit power with the corresponding frequency.

Meanwhile, in the case that efficiency is not improved by the frequencyvariation, an efficiency change may be measured by changing a voltagelevel or by varying other different power control variable.

In this case, the driving condition varying procedure may be performedintermittently for a stable operation of a wireless power transmittingand charging system, or may be performed with a predetermined timeinterval.

The device described herein may be implemented using softwarecomponents, and/or a combination of hardware components and softwarecomponents. For example, the device and the components described in theembodiments may be implemented by using a processor, a controller and anarithmetic logic unit (ALU), a digital signal processor, amicrocomputer, a field programmable array (FPA), a programmable logicunit (PLU), a microprocessor or one or more general purpose computers ora specific purpose computer such as any other device capable ofresponding to and executing instructions. The processing device may runan operating system (OS) and one or more software applications that areperformed on the OS. In addition, the processing device also may access,store, manipulate, process, and create data in response to execution ofthe software. For purpose of understanding, the description of aprocessing device is used as singular; however, one skilled in the artwill appreciated that a processing device may include multipleprocessing elements and/or multiple types of processing elements. Forexample, a processing device may include multiple processors or aprocessor and a controller. In addition, different processingconfigurations are also available, such as parallel processors.

The software may include a computer program, a code, an instruction, orsome combination thereof, to independently or collectively instruct soas to configure the processing device to operate as desired. Softwareand/or data may be embodied permanently or temporarily in any type ofmachine, component, physical device or virtual equipment, computerstorage medium or device, or in a propagated signal wave capable ofproviding instructions or data to or being interpreted by the processingdevice. The software also may be distributed over network coupledcomputer systems so that the software is stored and executed in adistributed fashion. The software and data may be stored by one or morecomputer readable recording media.

The methods according to the above-described example embodiments may berecorded in computer-readable media including program instructions toimplement various operations of the above-described example embodiments.The computer-readable media may also include, alone or in combinationwith the program instructions, data files, data structures, and thelike. According to at least some example embodiments, the programinstructions recorded on the media may be those specially designed andconstructed for the purposes of example embodiments. Examples of thecomputer-readable media include magnetic media such as hard disks,floppy disks, and magnetic tape; optical media such as CD-ROMs and DVDs;magneto-optical media such as floptical discs; and hardware devices thatare specially configured to store and perform program instructions, suchas ROM, RAM, flash memory and the like. Examples of program instructionsinclude both machine code, such as produced by a compiler and a higherlevel code that may be executed by the computer using an interpreter.The above-described devices may be configured to act as one or moresoftware modules in order to perform the operations of theabove-described embodiments, or vice versa.

Although the embodiments so far have been described with limitedembodiments and drawings, it will be obvious that various changes andmodifications may be available from the description for a person skilledin the art. For example, even though the descriptions are performed indifferent order from the described method, and/or the constituentcomponents such as the system, the structure, the device, the circuit,and so on described above are coupled or combined with different shapesfrom the described method or substituted, the proper result can beattained.

Accordingly, other implements, other embodiments and the equivalentswith patent claims are belonged to the scope of the following patentclaims.

1. A method for transmitting wireless power and operating a powertransmitter of a charge system, comprising: maintaining a ping valuetable where a ping signal condition is mapped to each height of a powerreceiver; detecting the power receiver by varying a ping signalaccording to the ping signal condition recorded in the ping value table;and controlling a charge mode according to a message received from thepower receiver.
 2. The method for transmitting wireless power andoperating a power transmitter of a charge system of claim 1, wherein theping signal condition is at least one of a frequency of the ping signalcollected at each height, a voltage level of the ping signal and a dutyratio of the ping signal.
 3. The method for transmitting wireless powerand operating a power transmitter of a charge system of claim 1, whereindetecting the power receiver includes a process of storing a ping signalcondition which is successful in detecting the power receiver, whereinthe ping signal condition successful in detecting the power receiver isset as an initial value for varying the ping signal.
 4. The method fortransmitting wireless power and operating a power transmitter of acharge system of claim 1, wherein controlling the charge mode includes:a process of identifying an initial driving condition mapped to the pingsignal condition successful in detecting the power receiver; and aprocess of performing wireless charge based on the initial drivingcondition.
 5. The method for transmitting wireless power and operating apower transmitter of a charge system of claim 4, wherein the initialdriving condition mapped to the ping signal condition is identical tothe ping signal condition successful in detecting the power receiver. 6.The method for transmitting wireless power and operating a powertransmitter of a charge system of claim 4, wherein the initial drivingcondition mapped to the ping signal condition is at least one of adriving frequency for wireless charge, voltage level and a constantvalue of Proportional Integral Differential (PID) algorithm.
 7. Themethod for transmitting wireless power and operating a power transmitterof a charge system of claim 4, wherein the initial driving conditionmapped to the ping signal condition is identified by a look-up table inwhich an optimized value measured in advance for each height of thepower receiver is recorded.
 8. The method for transmitting wirelesspower and operating a power transmitter of a charge system of claim 4,wherein the process of performing wireless charge includes startingwireless charge with the initial driving condition, performing a drivingcondition varying procedure which varies at least one of the drivingfrequency and the voltage level, and terminating or continuing thedriving condition varying procedure according to whether a powertransmission efficiency is improved.
 9. A device for transmittingwireless power and a power transmitter of a charge system, comprising: amemory in which a ping value table where a ping signal condition ismapped to each height of a power receiver is stored; a detecting unitfor detecting the power receiver by varying a ping signal according tothe ping signal condition recorded in the ping value table; and a chargemode control unit for controlling a charge mode according to a messagereceived from the power receiver.
 10. The device for transmittingwireless power and a power transmitter of a charge system of claim 9,wherein the ping signal condition is at least one of a frequency of theping signal collected at each height, a voltage level of the ping signaland a duty ratio of the ping signal.
 11. The device for transmittingwireless power and a power transmitter of a charge system of claim 9,wherein the detecting unit detects the power receiver includes a processof storing a ping signal condition successful in detecting the powerreceiver, and sets the ping signal condition successful in detecting thepower receiver as an initial value for varying the ping signal.
 12. Thedevice for transmitting wireless power and a power transmitter of acharge system of claim 9, wherein the charge mode control unitidentifies an initial driving condition mapped to the ping signalcondition successful in detecting the power receiver and performswireless charge based on the initial driving condition.
 13. The devicefor transmitting wireless power and a power transmitter of a chargesystem of claim 12, wherein the initial driving condition mapped to theping signal condition is identical to the ping signal conditionsuccessful in detecting the power receiver.
 14. The device fortransmitting wireless power and a power transmitter of a charge systemof claim 12, wherein the initial driving condition mapped to the pingsignal condition is at least one of a driving frequency for wirelesscharge, voltage level and a constant value of Proportional IntegralDifferential (PID) algorithm.
 15. The device for transmitting wirelesspower and a power transmitter of a charge system of claim 12, whereinthe memory further includes a look-up table in which an optimized valueof a driving condition mapped to the ping signal condition for eachheight of the power receiver is stored.
 16. The device for transmittingwireless power and a power transmitter of a charge system of claim 12,wherein the charge mode control unit performs a driving conditionvarying procedure which varies at least one of the driving frequency andthe voltage level, and terminates or continues the driving conditionvarying procedure according to whether a power transmission efficiencyis improved.